Articles, such as absorbent articles, are useful for absorbing many types of fluids, including fluids secreted or eliminated by the human body. Superabsorbent polymers (SAPs) are frequently used in absorbent articles to help improve the absorbent properties of such articles. SAPs are generally polymer based and are available in many forms, such as powders, granules, microparticles, films and fibers, for example. Upon contact with fluids, such SAPs swell by absorbing the fluids into their structures. In general, SAPs can absorb fluids insulted into such articles, and can retain such fluids to help prevent leakage and to help provide a dry feel even after fluid insult. Superabsorbent materials are often combined with water-insoluble fibers to create an absorbent composite for use in an absorbent core of an absorbent article.
There is a continuing effort to improve the performance of absorbent articles, especially at high levels of fluid saturation, to thereby reduce the occurrence of leakage and to improve fit and comfort. This is particularly significant when such articles are subjected to repeated fluid insults during use. This has become an increasing challenge as recent efforts in absorbent article design have generally focused on using higher concentrations of superabsorbent material and less fluff fiber to make the absorbent structures thinner and more flexible. However, notwithstanding the increase in total absorbent capacity obtained by increasing the concentration of superabsorbent material, such absorbent articles may still nevertheless leak during use. Such leakage may in part be the result of the absorbent core of an article having a high wet bulk in the fluid insult target zone. A high wet bulk can lead to cracking or fluid being squeezed out of the composite due to higher pressure caused by the swelling in the target zone, as well as general discomfort by the user. Therefore, there is a need for an absorbent composite which provides a reduced wet bulk in the target zone as compared to composites utilizing conventional SAPs, while generally maintaining fluid intake rate performance.
In addition, such high wet bulk may in part be the result of the absorbent composite having an insufficient fluid distribution. Poor fluid distribution decreases the full utility efficiency of absorbent composites as not all the superabsorbent material is absorbing liquid, particularly in areas located outside of the target zone. Fluid distribution in an absorbent composite is generally dependent on the amount of free liquid available for distribution, the structure and materials of the absorbent composite, and a time factor. Conventional SAPs tend to swell in the insult target zone at a moderate rate until either an entire fluid insult rate has been consumed, or until the SAP has reached its saturation point. The result is an absorbent composite that has a high wet bulk and typically does not provide desirable fluid distribution within an absorbent article. Therefore, there is a need for an absorbent composite which provides improved fluid distribution within an absorbent article as compared to composites utilizing conventional SAPs, while generally maintaining fluid intake rate performance.